Real-value encryption of digital image utilizing fractional Fourier transform

A novel method of digital image real-value encryption is presented by utilizing a novel reality-preserving fractional Fourier transform. Image encryption and decryption are performed based on the real-valuedness and index additivity of the reality-preserving fractional Fourier transform. The input and encrypted data are respectively in the spatial domain and the reality-preserving fractional Fourier transformed domain determined by encryption keys. It resists statistic analyses effectively. In addition, the encrypted image is real-valued, so it's convenient for display and storage. The simulation result shows that as a method of encryption with simple keys, it doesn't bring data expanding, and is sensitive to parameters, with considerable robustness and security, which has a good prospect and practicability in information security field.